Effect of nickel and selenium co-doping on molybdenum disulfide structure and its electrochemical activity in polysulfide electrolyte

Abstract

The development of a low-cost, and highly effective platinum (Pt)-free counter electrode (CE) that is highly stable towards polysulfide electrolyte presents a substantial challenge. Trigonal Molybdenum disulfide (1T-MoS _2 ) has shown good chemical stability toward polysulfide electrolytes. In this study, 1T-MoS _2 was prepared by co-doping with nickel (Ni) and selenium (Se) into MoS _2 through hydrothermal method and utilizing its reduction activity toward polysulfide electrolyte. According to electrochemical impedance spectroscopy (EIS) analysis, Ni-Se-MoS _2 has a low charge transfer resistance and electron recombination lifetime. In addition, cyclic voltmeter (CV) analysis reveals a high absolute area indicating a high level of electrocatalytic activity for polysulfide reduction at the electrolyte/counter electrode (CE) interface. The XRD analysis shows that the phase shifting of 2H MoS _2 to 1 T MoS _2 and the intensity of the co-doped sample is lower than that of others. SEM analysis reveals a microsphere-flower-like morphology that increases specific surface area.

Keywords

• counter electrode
• polysulfide
• quantum dot sensitized solar cell
• electrocatalytic activity